Tensile Strength of Continuous and Disordered Fibrous Mats: A Tale of Two-Length Scales

Continuous and disordered fibrous mats are ubiquitous multi-scalar materials endowed with diverse functionalities and nonlinear mechanical properties. Gaining deeper insights into mechanical properties, such as tensile strength and breaking elongation, can broaden the scope of potential applications for these fibrous mats across various fields. Here, a unified tensile strength model applicable to electrospun and melt-blown mats is presented that hinges on the tensile strength of constituent fibers, fiber orientation, fiber volume fraction, and the specimen dimensions considered during uniaxial tensile testing. Espoused by the established body of literature, fiber stretching has been considered a key deformation mechanism for predicting the tensile strength of these fibrous mats. Regardless of inconsistencies and anomalies in fiber morphology, a good agreement has been obtained between the theoretical and experimental values of tensile strengths of polylactic acid (PLA)-based electrospun and polypropylene-based melt-blown mats. The model's robustness is evident in its successful prediction of a nearly two-order magnitude reduction in tensile strength for electrospun mats compared to their constituent fibers. A roadmap to enhance the tensile strength of fibrous mats has been developed by analyzing key fiber and structural parameters. Further, higher-order nematic orientation parameters quantified anisotropy in the fibrous mats before and after tensile loading.